This came from my wife's grandfather. I don't know exactly the year it's from, but the earliest ad I could find was from the December 1969 Popular Mechanics:
http://books.google.com/books?id=LNgDAAAAMBAJ&lpg=PA35&dq=what%20year%20was%20the%20versamatic%20model%20no%204100%20made%3F&pg=PA35#v=onepage&q&f=false